Construction Of The Dmx Termination - ProLights CROMOSPOT500 User Manual

DMX - INPUT
XLR plug
1 5
2 4
3
ATTENTION
The screened parts of the cable (sleeve) must never be connected to the system's earth, as this would cause
faulty fixture and controller operation.
Over long runs can be necessary to insert a DMX level matching amplifier.
For those connections the use of balanced microphone cable is not recommended because it cannot trans-
mit control DMX data reliably.
• Connect the controller DMX input to the DMX output of the first unit.
• Connect the DMX output to the DMX input of the following unit. Connect again the output to the input
of the following unit until all the units are connected in chain.
• When the signal cable has to run longer distance is recommended to insert a DMX termination on the
last unit.

3.10 Construction of the DMX termination

The termination avoids the risk of DMX 512 signals being reflected back along the cable when they reaches
the end of the line: under certain conditions and with certain cable lengths, this could cause them to cancel
the original signals. The termination has to be prepared by soldering a 120Ω 1/4 W resistor on the last ele-
ment of the DMX chain, between pins 2 and 3 of the 5 pin or 3 pin male XLR connector, as shown in figure.
1
2
120
CROMOSPOT500
Pin1 : Ground
Pin2 : - Negative
1 2
Pin3 : + Positive
3
Pin4 : N/C
Pin5 : N/C
5
1
3
4
3
2
120
DMX - OUTPUT
XLR socket
5
2 1
3
4
2
3
1
Example:
5 pin and 3 pin XLR connector
13
1
2
3